/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.catalina.tribes.tipis;

import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.io.Serializable;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Map;
import java.util.Set;

import org.apache.catalina.tribes.Channel;
import org.apache.catalina.tribes.ChannelException;
import org.apache.catalina.tribes.ChannelException.FaultyMember;
import org.apache.catalina.tribes.ChannelListener;
import org.apache.catalina.tribes.Heartbeat;
import org.apache.catalina.tribes.Member;
import org.apache.catalina.tribes.MembershipListener;
import org.apache.catalina.tribes.group.Response;
import org.apache.catalina.tribes.group.RpcCallback;
import org.apache.catalina.tribes.group.RpcChannel;
import org.apache.catalina.tribes.io.XByteBuffer;
import org.apache.catalina.tribes.membership.MemberImpl;
import org.apache.catalina.tribes.util.Arrays;
import org.apache.juli.logging.Log;
import org.apache.juli.logging.LogFactory;
import java.util.concurrent.ConcurrentHashMap;

/**
 * 
 * @author Filip Hanik
 * @version 1.0
 */
public abstract class AbstractReplicatedMap extends ConcurrentHashMap implements
		RpcCallback, ChannelListener, MembershipListener, Heartbeat {
	protected static Log log = LogFactory.getLog(AbstractReplicatedMap.class);

	/**
	 * The default initial capacity - MUST be a power of two.
	 */
	public static final int DEFAULT_INITIAL_CAPACITY = 16;

	/**
	 * The load factor used when none specified in constructor.
	 **/
	public static final float DEFAULT_LOAD_FACTOR = 0.75f;

	/**
	 * Used to identify the map
	 */
	final String chset = "ISO-8859-1";

	// ------------------------------------------------------------------------------
	// INSTANCE VARIABLES
	// ------------------------------------------------------------------------------
	protected abstract int getStateMessageType();

	/**
	 * Timeout for RPC messages, how long we will wait for a reply
	 */
	protected transient long rpcTimeout = 5000;
	/**
	 * Reference to the channel for sending messages
	 */
	protected transient Channel channel;
	/**
	 * The RpcChannel to send RPC messages through
	 */
	protected transient RpcChannel rpcChannel;
	/**
	 * The Map context name makes this map unique, this allows us to have more
	 * than one map shared through one channel
	 */
	protected transient byte[] mapContextName;
	/**
	 * Has the state been transferred
	 */
	protected transient boolean stateTransferred = false;
	/**
	 * Simple lock object for transfers
	 */
	protected transient Object stateMutex = new Object();
	/**
	 * A list of members in our map
	 */
	protected transient HashMap mapMembers = new HashMap();
	/**
	 * Our default send options
	 */
	protected transient int channelSendOptions = Channel.SEND_OPTIONS_DEFAULT;
	/**
	 * The owner of this map, ala a SessionManager for example
	 */
	protected transient MapOwner mapOwner;
	/**
	 * External class loaders if serialization and deserialization is to be
	 * performed successfully.
	 */
	protected transient ClassLoader[] externalLoaders;

	/**
	 * The node we are currently backing up data to, this index will rotate on a
	 * round robin basis
	 */
	protected transient int currentNode = 0;

	/**
	 * Since the map keeps internal membership this is the timeout for a ping
	 * message to be responded to If a remote map doesn't respond within this
	 * timeframe, its considered dead.
	 */
	protected transient long accessTimeout = 5000;

	/**
	 * Readable string of the mapContextName value
	 */
	protected transient String mapname = "";

	// ------------------------------------------------------------------------------
	// map owner interface
	// ------------------------------------------------------------------------------

	public static interface MapOwner {
		public void objectMadePrimay(Object key, Object value);
	}

	// ------------------------------------------------------------------------------
	// CONSTRUCTORS
	// ------------------------------------------------------------------------------

	/**
	 * Creates a new map
	 * 
	 * @param channel
	 *            The channel to use for communication
	 * @param timeout
	 *            long - timeout for RPC messags
	 * @param mapContextName
	 *            String - unique name for this map, to allow multiple maps per
	 *            channel
	 * @param initialCapacity
	 *            int - the size of this map, see HashMap
	 * @param loadFactor
	 *            float - load factor, see HashMap
	 * @param cls
	 *            - a list of classloaders to be used for deserialization of
	 *            objects.
	 */
	public AbstractReplicatedMap(MapOwner owner, Channel channel, long timeout,
			String mapContextName, int initialCapacity, float loadFactor,
			int channelSendOptions, ClassLoader[] cls) {
		super(initialCapacity, loadFactor, 15);
		init(owner, channel, mapContextName, timeout, channelSendOptions, cls);

	}

	/**
	 * Helper methods, wraps a single member in an array
	 * 
	 * @param m
	 *            Member
	 * @return Member[]
	 */
	protected Member[] wrap(Member m) {
		if (m == null)
			return new Member[0];
		else
			return new Member[] { m };
	}

	/**
	 * Initializes the map by creating the RPC channel, registering itself as a
	 * channel listener This method is also responsible for initiating the state
	 * transfer
	 * 
	 * @param owner
	 *            Object
	 * @param channel
	 *            Channel
	 * @param mapContextName
	 *            String
	 * @param timeout
	 *            long
	 * @param channelSendOptions
	 *            int
	 * @param cls
	 *            ClassLoader[]
	 */
	protected void init(MapOwner owner, Channel channel, String mapContextName,
			long timeout, int channelSendOptions, ClassLoader[] cls) {
		log.info("Initializing AbstractReplicatedMap with context name:"
				+ mapContextName);
		this.mapOwner = owner;
		this.externalLoaders = cls;
		this.channelSendOptions = channelSendOptions;
		this.channel = channel;
		this.rpcTimeout = timeout;

		try {
			this.mapname = mapContextName;
			// unique context is more efficient if it is stored as bytes
			this.mapContextName = mapContextName.getBytes(chset);
		} catch (UnsupportedEncodingException x) {
			log.warn("Unable to encode mapContextName[" + mapContextName
					+ "] using getBytes(" + chset
					+ ") using default getBytes()", x);
			this.mapContextName = mapContextName.getBytes();
		}
		if (log.isTraceEnabled())
			log.trace("Created Lazy Map with name:" + mapContextName
					+ ", bytes:" + Arrays.toString(this.mapContextName));

		// create an rpc channel and add the map as a listener
		this.rpcChannel = new RpcChannel(this.mapContextName, channel, this);
		// add this map as a message listener
		this.channel.addChannelListener(this);
		// listen for membership notifications
		this.channel.addMembershipListener(this);

		try {
			// broadcast our map, this just notifies other members of our
			// existence
			broadcast(MapMessage.MSG_INIT, true);
			// transfer state from another map
			transferState();
			// state is transferred, we are ready for messaging
			broadcast(MapMessage.MSG_START, true);
		} catch (ChannelException x) {
			log.warn("Unable to send map start message.");
			// remove listener from channel
			this.rpcChannel.breakdown();
			this.channel.removeChannelListener(this);
			this.channel.removeMembershipListener(this);
			throw new RuntimeException("Unable to start replicated map.", x);
		}
	}

	/**
	 * Sends a ping out to all the members in the cluster, not just map members
	 * that this map is alive.
	 * 
	 * @param timeout
	 *            long
	 * @throws ChannelException
	 */
	protected void ping(long timeout) throws ChannelException {
		// send out a map membership message, only wait for the first reply
		MapMessage msg = new MapMessage(this.mapContextName,
				MapMessage.MSG_INIT, false, null, null, null, channel
						.getLocalMember(false), null);
		if (channel.getMembers().length > 0) {
			try {
				// send a ping, wait for all nodes to reply
				Response[] resp = rpcChannel.send(channel.getMembers(), msg,
						rpcChannel.ALL_REPLY, (channelSendOptions),
						(int) accessTimeout);
				for (int i = 0; i < resp.length; i++) {
					memberAlive(resp[i].getSource());
				}
			} catch (ChannelException ce) {
				// Handle known failed members
				FaultyMember[] faultyMembers = ce.getFaultyMembers();
				for (FaultyMember faultyMember : faultyMembers) {
					memberDisappeared(faultyMember.getMember());
				}
			}
		}
		// update our map of members, expire some if we didn't receive a ping
		// back
		synchronized (mapMembers) {
			Iterator it = mapMembers.entrySet().iterator();
			long now = System.currentTimeMillis();
			while (it.hasNext()) {
				Map.Entry entry = (Map.Entry) it.next();
				long access = ((Long) entry.getValue()).longValue();
				if ((now - access) > timeout) {
					it.remove();
					memberDisappeared((Member) entry.getKey());
				}
			}
		}// synch
	}

	/**
	 * We have received a member alive notification
	 * 
	 * @param member
	 *            Member
	 */
	protected void memberAlive(Member member) {
		synchronized (mapMembers) {
			if (!mapMembers.containsKey(member)) {
				mapMemberAdded(member);
			} // end if
			mapMembers.put(member, new Long(System.currentTimeMillis()));
		}
	}

	/**
	 * Helper method to broadcast a message to all members in a channel
	 * 
	 * @param msgtype
	 *            int
	 * @param rpc
	 *            boolean
	 * @throws ChannelException
	 */
	protected void broadcast(int msgtype, boolean rpc) throws ChannelException {
		// send out a map membership message, only wait for the first reply
		MapMessage msg = new MapMessage(this.mapContextName, msgtype, false,
				null, null, null, channel.getLocalMember(false), null);
		if (rpc) {
			Response[] resp = rpcChannel.send(channel.getMembers(), msg,
					rpcChannel.FIRST_REPLY, (channelSendOptions), rpcTimeout);
			for (int i = 0; i < resp.length; i++) {
				mapMemberAdded(resp[i].getSource());
				messageReceived(resp[i].getMessage(), resp[i].getSource());
			}
		} else {
			channel.send(channel.getMembers(), msg, channelSendOptions);
		}
	}

	public void breakdown() {
		finalize();
	}

	public void finalize() {
		try {
			broadcast(MapMessage.MSG_STOP, false);
		} catch (Exception ignore) {
		}
		// cleanup
		if (this.rpcChannel != null) {
			this.rpcChannel.breakdown();
		}
		if (this.channel != null) {
			this.channel.removeChannelListener(this);
			this.channel.removeMembershipListener(this);
		}
		this.rpcChannel = null;
		this.channel = null;
		this.mapMembers.clear();
		super.clear();
		this.stateTransferred = false;
		this.externalLoaders = null;
	}

	public int hashCode() {
		return Arrays.hashCode(this.mapContextName);
	}

	public boolean equals(Object o) {
		if (o == null)
			return false;
		if (!(o instanceof AbstractReplicatedMap))
			return false;
		if (!(o.getClass().equals(this.getClass())))
			return false;
		AbstractReplicatedMap other = (AbstractReplicatedMap) o;
		return Arrays.equals(mapContextName, other.mapContextName);
	}

	// ------------------------------------------------------------------------------
	// GROUP COM INTERFACES
	// ------------------------------------------------------------------------------
	public Member[] getMapMembers(HashMap members) {
		synchronized (members) {
			Member[] result = new Member[members.size()];
			members.keySet().toArray(result);
			return result;
		}
	}

	public Member[] getMapMembers() {
		return getMapMembers(this.mapMembers);
	}

	public Member[] getMapMembersExcl(Member[] exclude) {
		synchronized (mapMembers) {
			HashMap list = (HashMap) mapMembers.clone();
			for (int i = 0; i < exclude.length; i++)
				list.remove(exclude[i]);
			return getMapMembers(list);
		}
	}

	/**
	 * Replicates any changes to the object since the last time The object has
	 * to be primary, ie, if the object is a proxy or a backup, it will not be
	 * replicated<br>
	 * 
	 * @param complete
	 *            - if set to true, the object is replicated to its backup if
	 *            set to false, only objects that implement ReplicatedMapEntry
	 *            and the isDirty() returns true will be replicated
	 */
	public void replicate(Object key, boolean complete) {
		if (log.isTraceEnabled())
			log.trace("Replicate invoked on key:" + key);
		MapEntry entry = (MapEntry) super.get(key);
		if (entry == null)
			return;
		if (!entry.isSerializable())
			return;
		if (entry != null && entry.isPrimary()
				&& entry.getBackupNodes() != null
				&& entry.getBackupNodes().length > 0) {
			Object value = entry.getValue();
			// check to see if we need to replicate this object
			// isDirty()||complete
			boolean repl = complete
					|| ((value instanceof ReplicatedMapEntry) && ((ReplicatedMapEntry) value)
							.isDirty());

			if (!repl) {
				if (log.isTraceEnabled())
					log.trace("Not replicating:" + key + ", no change made");

				return;
			}
			// check to see if the message is diffable
			boolean diff = ((value instanceof ReplicatedMapEntry) && ((ReplicatedMapEntry) value)
					.isDiffable());
			MapMessage msg = null;
			if (diff) {
				ReplicatedMapEntry rentry = (ReplicatedMapEntry) entry
						.getValue();
				try {
					rentry.lock();
					// construct a diff message
					msg = new MapMessage(mapContextName, MapMessage.MSG_BACKUP,
							true, (Serializable) entry.getKey(), null, rentry
									.getDiff(), entry.getPrimary(), entry
									.getBackupNodes());
					rentry.resetDiff();
				} catch (IOException x) {
					log
							.error(
									"Unable to diff object. Will replicate the entire object instead.",
									x);
				} finally {
					rentry.unlock();
				}

			}
			if (msg == null) {
				// construct a complete
				msg = new MapMessage(mapContextName, MapMessage.MSG_BACKUP,
						false, (Serializable) entry.getKey(),
						(Serializable) entry.getValue(), null, entry
								.getPrimary(), entry.getBackupNodes());

			}
			try {
				if (channel != null && entry.getBackupNodes() != null
						&& entry.getBackupNodes().length > 0) {
					channel.send(entry.getBackupNodes(), msg,
							channelSendOptions);
				}
			} catch (ChannelException x) {
				log.error("Unable to replicate data.", x);
			}
		} // end if

	}

	/**
	 * This can be invoked by a periodic thread to replicate out any changes.
	 * For maps that don't store objects that implement ReplicatedMapEntry, this
	 * method should be used infrequently to avoid large amounts of data
	 * transfer
	 * 
	 * @param complete
	 *            boolean
	 */
	public void replicate(boolean complete) {
		Iterator i = super.entrySet().iterator();
		while (i.hasNext()) {
			Map.Entry e = (Map.Entry) i.next();
			replicate(e.getKey(), complete);
		} // while

	}

	public void transferState() {
		try {
			Member[] members = getMapMembers();
			Member backup = members.length > 0 ? (Member) members[0] : null;
			if (backup != null) {
				MapMessage msg = new MapMessage(mapContextName,
						getStateMessageType(), false, null, null, null, null,
						null);
				Response[] resp = rpcChannel.send(new Member[] { backup }, msg,
						rpcChannel.FIRST_REPLY, channelSendOptions, rpcTimeout);
				if (resp.length > 0) {
					synchronized (stateMutex) {
						msg = (MapMessage) resp[0].getMessage();
						msg.deserialize(getExternalLoaders());
						ArrayList list = (ArrayList) msg.getValue();
						for (int i = 0; i < list.size(); i++) {
							messageReceived((Serializable) list.get(i), resp[0]
									.getSource());
						} // for
					}
				} else {
					log.warn("Transfer state, 0 replies, probably a timeout.");
				}
			}
		} catch (ChannelException x) {
			log.error("Unable to transfer LazyReplicatedMap state.", x);
		} catch (IOException x) {
			log.error("Unable to transfer LazyReplicatedMap state.", x);
		} catch (ClassNotFoundException x) {
			log.error("Unable to transfer LazyReplicatedMap state.", x);
		}
		stateTransferred = true;
	}

	/**
	 * @todo implement state transfer
	 * @param msg
	 *            Serializable
	 * @return Serializable - null if no reply should be sent
	 */
	public Serializable replyRequest(Serializable msg, final Member sender) {
		if (!(msg instanceof MapMessage))
			return null;
		MapMessage mapmsg = (MapMessage) msg;

		// map init request
		if (mapmsg.getMsgType() == mapmsg.MSG_INIT) {
			mapmsg.setPrimary(channel.getLocalMember(false));
			return mapmsg;
		}

		// map start request
		if (mapmsg.getMsgType() == mapmsg.MSG_START) {
			mapmsg.setPrimary(channel.getLocalMember(false));
			mapMemberAdded(sender);
			return mapmsg;
		}

		// backup request
		if (mapmsg.getMsgType() == mapmsg.MSG_RETRIEVE_BACKUP) {
			MapEntry entry = (MapEntry) super.get(mapmsg.getKey());
			if (entry == null || (!entry.isSerializable()))
				return null;
			mapmsg.setValue((Serializable) entry.getValue());
			return mapmsg;
		}

		// state transfer request
		if (mapmsg.getMsgType() == mapmsg.MSG_STATE
				|| mapmsg.getMsgType() == mapmsg.MSG_STATE_COPY) {
			synchronized (stateMutex) { // make sure we dont do two things at
										// the same time
				ArrayList list = new ArrayList();
				Iterator i = super.entrySet().iterator();
				while (i.hasNext()) {
					Map.Entry e = (Map.Entry) i.next();
					MapEntry entry = (MapEntry) super.get(e.getKey());
					if (entry != null && entry.isSerializable()) {
						boolean copy = (mapmsg.getMsgType() == mapmsg.MSG_STATE_COPY);
						MapMessage me = new MapMessage(mapContextName,
								copy ? MapMessage.MSG_COPY
										: MapMessage.MSG_PROXY, false,
								(Serializable) entry.getKey(),
								copy ? (Serializable) entry.getValue() : null,
								null, entry.getPrimary(), entry
										.getBackupNodes());
						list.add(me);
					}
				}
				mapmsg.setValue(list);
				return mapmsg;

			} // synchronized
		}

		return null;

	}

	/**
	 * If the reply has already been sent to the requesting thread, the rpc
	 * callback can handle any data that comes in after the fact.
	 * 
	 * @param msg
	 *            Serializable
	 * @param sender
	 *            Member
	 */
	public void leftOver(Serializable msg, Member sender) {
		// left over membership messages
		if (!(msg instanceof MapMessage))
			return;

		MapMessage mapmsg = (MapMessage) msg;
		try {
			mapmsg.deserialize(getExternalLoaders());
			if (mapmsg.getMsgType() == MapMessage.MSG_START) {
				mapMemberAdded(mapmsg.getPrimary());
			} else if (mapmsg.getMsgType() == MapMessage.MSG_INIT) {
				memberAlive(mapmsg.getPrimary());
			}
		} catch (IOException x) {
			log.error("Unable to deserialize MapMessage.", x);
		} catch (ClassNotFoundException x) {
			log.error("Unable to deserialize MapMessage.", x);
		}
	}

	public void messageReceived(Serializable msg, Member sender) {
		if (!(msg instanceof MapMessage))
			return;

		MapMessage mapmsg = (MapMessage) msg;
		if (log.isTraceEnabled()) {
			log.trace("Map[" + mapname + "] received message:" + mapmsg);
		}

		try {
			mapmsg.deserialize(getExternalLoaders());
		} catch (IOException x) {
			log.error("Unable to deserialize MapMessage.", x);
			return;
		} catch (ClassNotFoundException x) {
			log.error("Unable to deserialize MapMessage.", x);
			return;
		}
		if (log.isTraceEnabled())
			log.trace("Map message received from:" + sender.getName() + " msg:"
					+ mapmsg);
		if (mapmsg.getMsgType() == MapMessage.MSG_START) {
			mapMemberAdded(mapmsg.getPrimary());
		}

		if (mapmsg.getMsgType() == MapMessage.MSG_STOP) {
			memberDisappeared(mapmsg.getPrimary());
		}

		if (mapmsg.getMsgType() == MapMessage.MSG_PROXY) {
			MapEntry entry = (MapEntry) super.get(mapmsg.getKey());
			if (entry == null) {
				entry = new MapEntry(mapmsg.getKey(), mapmsg.getValue());
				entry.setBackup(false);
				entry.setProxy(true);
				entry.setBackupNodes(mapmsg.getBackupNodes());
				entry.setPrimary(mapmsg.getPrimary());
				super.put(entry.getKey(), entry);
			} else {
				entry.setProxy(true);
				entry.setBackup(false);
				entry.setBackupNodes(mapmsg.getBackupNodes());
				entry.setPrimary(mapmsg.getPrimary());
			}
		}

		if (mapmsg.getMsgType() == MapMessage.MSG_REMOVE) {
			super.remove(mapmsg.getKey());
		}

		if (mapmsg.getMsgType() == MapMessage.MSG_BACKUP
				|| mapmsg.getMsgType() == MapMessage.MSG_COPY) {
			MapEntry entry = (MapEntry) super.get(mapmsg.getKey());
			if (entry == null) {
				entry = new MapEntry(mapmsg.getKey(), mapmsg.getValue());
				entry.setBackup(mapmsg.getMsgType() == MapMessage.MSG_BACKUP);
				entry.setProxy(false);
				entry.setBackupNodes(mapmsg.getBackupNodes());
				entry.setPrimary(mapmsg.getPrimary());
				if (mapmsg.getValue() != null
						&& mapmsg.getValue() instanceof ReplicatedMapEntry) {
					((ReplicatedMapEntry) mapmsg.getValue())
							.setOwner(getMapOwner());
				}
			} else {
				entry.setBackup(mapmsg.getMsgType() == MapMessage.MSG_BACKUP);
				entry.setProxy(false);
				entry.setBackupNodes(mapmsg.getBackupNodes());
				entry.setPrimary(mapmsg.getPrimary());
				if (entry.getValue() instanceof ReplicatedMapEntry) {
					ReplicatedMapEntry diff = (ReplicatedMapEntry) entry
							.getValue();
					if (mapmsg.isDiff()) {
						try {
							diff.lock();
							diff.applyDiff(mapmsg.getDiffValue(), 0, mapmsg
									.getDiffValue().length);
						} catch (Exception x) {
							log.error("Unable to apply diff to key:"
									+ entry.getKey(), x);
						} finally {
							diff.unlock();
						}
					} else {
						if (mapmsg.getValue() != null)
							entry.setValue(mapmsg.getValue());
						((ReplicatedMapEntry) entry.getValue())
								.setOwner(getMapOwner());
					} // end if
				} else if (mapmsg.getValue() instanceof ReplicatedMapEntry) {
					ReplicatedMapEntry re = (ReplicatedMapEntry) mapmsg
							.getValue();
					re.setOwner(getMapOwner());
					entry.setValue(re);
				} else {
					if (mapmsg.getValue() != null)
						entry.setValue(mapmsg.getValue());
				} // end if
			} // end if
			super.put(entry.getKey(), entry);
		} // end if
	}

	public boolean accept(Serializable msg, Member sender) {
		boolean result = false;
		if (msg instanceof MapMessage) {
			if (log.isTraceEnabled())
				log.trace("Map[" + mapname + "] accepting...." + msg);
			result = Arrays.equals(mapContextName, ((MapMessage) msg)
					.getMapId());
			if (log.isTraceEnabled())
				log.trace("Msg[" + mapname + "] accepted[" + result + "]...."
						+ msg);
		}
		return result;
	}

	public void mapMemberAdded(Member member) {
		if (member.equals(getChannel().getLocalMember(false)))
			return;
		boolean memberAdded = false;
		// select a backup node if we don't have one
		synchronized (mapMembers) {
			if (!mapMembers.containsKey(member)) {
				mapMembers.put(member, new Long(System.currentTimeMillis()));
				memberAdded = true;
			}
		}
		if (memberAdded) {
			synchronized (stateMutex) {
				Iterator i = super.entrySet().iterator();
				while (i.hasNext()) {
					Map.Entry e = (Map.Entry) i.next();
					MapEntry entry = (MapEntry) super.get(e.getKey());
					if (entry == null)
						continue;
					if (entry.isPrimary()
							&& (entry.getBackupNodes() == null || entry
									.getBackupNodes().length == 0)) {
						try {
							Member[] backup = publishEntryInfo(entry.getKey(),
									entry.getValue());
							entry.setBackupNodes(backup);
							entry.setPrimary(channel.getLocalMember(false));
						} catch (ChannelException x) {
							log.error("Unable to select backup node.", x);
						} // catch
					} // end if
				} // while
			} // synchronized
		}// end if
	}

	public boolean inSet(Member m, Member[] set) {
		if (set == null)
			return false;
		boolean result = false;
		for (int i = 0; i < set.length && (!result); i++)
			if (m.equals(set[i]))
				result = true;
		return result;
	}

	public Member[] excludeFromSet(Member[] mbrs, Member[] set) {
		ArrayList result = new ArrayList();
		for (int i = 0; i < set.length; i++) {
			boolean include = true;
			for (int j = 0; j < mbrs.length; j++)
				if (mbrs[j].equals(set[i]))
					include = false;
			if (include)
				result.add(set[i]);
		}
		return (Member[]) result.toArray(new Member[result.size()]);
	}

	public void memberAdded(Member member) {
		// do nothing
	}

	public void memberDisappeared(Member member) {
		boolean removed = false;
		synchronized (mapMembers) {
			removed = (mapMembers.remove(member) != null);
			if (!removed) {
				if (log.isDebugEnabled())
					log.debug("Member[" + member
							+ "] disappeared, but was not present in the map.");
				return; // the member was not part of our map.
			}
		}

		Iterator i = super.entrySet().iterator();
		while (i.hasNext()) {
			Map.Entry e = (Map.Entry) i.next();
			MapEntry entry = (MapEntry) super.get(e.getKey());
			if (entry == null)
				continue;
			if (entry.isPrimary() && inSet(member, entry.getBackupNodes())) {
				if (log.isDebugEnabled())
					log.debug("[1] Primary choosing a new backup");
				try {
					Member[] backup = publishEntryInfo(entry.getKey(), entry
							.getValue());
					entry.setBackupNodes(backup);
					entry.setPrimary(channel.getLocalMember(false));
				} catch (ChannelException x) {
					log.error("Unable to relocate[" + entry.getKey()
							+ "] to a new backup node", x);
				}
			} else if (member.equals(entry.getPrimary())) {
				if (log.isDebugEnabled())
					log.debug("[2] Primary disappeared");
				entry.setPrimary(null);
			} // end if

			if (entry.isProxy() && entry.getPrimary() == null
					&& entry.getBackupNodes() != null
					&& entry.getBackupNodes().length == 1
					&& entry.getBackupNodes()[0].equals(member)) {
				// remove proxies that have no backup nor primaries
				if (log.isDebugEnabled())
					log.debug("[3] Removing orphaned proxy");
				i.remove();
			} else if (entry.getPrimary() == null
					&& entry.isBackup()
					&& entry.getBackupNodes() != null
					&& entry.getBackupNodes().length == 1
					&& entry.getBackupNodes()[0].equals(channel
							.getLocalMember(false))) {
				try {
					if (log.isDebugEnabled())
						log.debug("[4] Backup becoming primary");
					entry.setPrimary(channel.getLocalMember(false));
					entry.setBackup(false);
					entry.setProxy(false);
					Member[] backup = publishEntryInfo(entry.getKey(), entry
							.getValue());
					entry.setBackupNodes(backup);
					if (mapOwner != null)
						mapOwner.objectMadePrimay(entry.getKey(), entry
								.getValue());

				} catch (ChannelException x) {
					log.error("Unable to relocate[" + entry.getKey()
							+ "] to a new backup node", x);
				}
			}

		} // while
	}

	public int getNextBackupIndex() {
		int size = mapMembers.size();
		if (mapMembers.size() == 0)
			return -1;
		int node = currentNode++;
		if (node >= size) {
			node = 0;
			currentNode = 0;
		}
		return node;
	}

	public Member getNextBackupNode() {
		Member[] members = getMapMembers();
		int node = getNextBackupIndex();
		if (members.length == 0 || node == -1)
			return null;
		if (node >= members.length)
			node = 0;
		return members[node];
	}

	protected abstract Member[] publishEntryInfo(Object key, Object value)
			throws ChannelException;

	public void heartbeat() {
		try {
			ping(accessTimeout);
		} catch (Exception x) {
			log.error("Unable to send AbstractReplicatedMap.ping message", x);
		}
	}

	// ------------------------------------------------------------------------------
	// METHODS TO OVERRIDE
	// ------------------------------------------------------------------------------

	/**
	 * Removes an object from this map, it will also remove it from
	 * 
	 * @param key
	 *            Object
	 * @return Object
	 */
	public Object remove(Object key) {
		return remove(key, true);
	}

	public Object remove(Object key, boolean notify) {
		MapEntry entry = (MapEntry) super.remove(key);

		try {
			if (getMapMembers().length > 0 && notify) {
				MapMessage msg = new MapMessage(getMapContextName(),
						MapMessage.MSG_REMOVE, false, (Serializable) key, null,
						null, null, null);
				getChannel()
						.send(getMapMembers(), msg, getChannelSendOptions());
			}
		} catch (ChannelException x) {
			log
					.error(
							"Unable to replicate out data for a LazyReplicatedMap.remove operation",
							x);
		}
		return entry != null ? entry.getValue() : null;
	}

	public MapEntry getInternal(Object key) {
		return (MapEntry) super.get(key);
	}

	public Object get(Object key) {
		MapEntry entry = (MapEntry) super.get(key);
		if (log.isTraceEnabled())
			log.trace("Requesting id:" + key + " entry:" + entry);
		if (entry == null)
			return null;
		if (!entry.isPrimary()) {
			// if the message is not primary, we need to retrieve the latest
			// value
			try {
				Member[] backup = null;
				MapMessage msg = null;
				if (!entry.isBackup()) {
					// make sure we don't retrieve from ourselves
					msg = new MapMessage(getMapContextName(),
							MapMessage.MSG_RETRIEVE_BACKUP, false,
							(Serializable) key, null, null, null, null);
					Response[] resp = getRpcChannel().send(
							entry.getBackupNodes(), msg,
							this.getRpcChannel().FIRST_REPLY,
							Channel.SEND_OPTIONS_DEFAULT, getRpcTimeout());
					if (resp == null || resp.length == 0) {
						// no responses
						log.warn("Unable to retrieve remote object for key:"
								+ key);
						return null;
					}
					msg = (MapMessage) resp[0].getMessage();
					msg.deserialize(getExternalLoaders());
					backup = entry.getBackupNodes();
					if (entry.getValue() instanceof ReplicatedMapEntry) {
						ReplicatedMapEntry val = (ReplicatedMapEntry) entry
								.getValue();
						val.setOwner(getMapOwner());
					}
					if (msg.getValue() != null)
						entry.setValue(msg.getValue());
				}
				if (entry.isBackup()) {
					// select a new backup node
					backup = publishEntryInfo(key, entry.getValue());
				} else if (entry.isProxy()) {
					// invalidate the previous primary
					msg = new MapMessage(getMapContextName(),
							MapMessage.MSG_PROXY, false, (Serializable) key,
							null, null, channel.getLocalMember(false), backup);
					Member[] dest = getMapMembersExcl(backup);
					if (dest != null && dest.length > 0) {
						getChannel().send(dest, msg, getChannelSendOptions());
					}
					if (entry.getValue() != null
							&& entry.getValue() instanceof ReplicatedMapEntry) {
						ReplicatedMapEntry val = (ReplicatedMapEntry) entry
								.getValue();
						val.setOwner(getMapOwner());
					}
				}
				entry.setPrimary(channel.getLocalMember(false));
				entry.setBackupNodes(backup);
				entry.setBackup(false);
				entry.setProxy(false);
				if (getMapOwner() != null)
					getMapOwner().objectMadePrimay(key, entry.getValue());

			} catch (Exception x) {
				log
						.error(
								"Unable to replicate out data for a LazyReplicatedMap.get operation",
								x);
				return null;
			}
		}
		if (log.isTraceEnabled())
			log.trace("Requesting id:" + key + " result:" + entry.getValue());
		return entry.getValue();
	}

	protected void printMap(String header) {
		try {
			System.out.println("\nDEBUG MAP:" + header);
			System.out.println("Map[" + new String(mapContextName, chset)
					+ ", Map Size:" + super.size());
			Member[] mbrs = getMapMembers();
			for (int i = 0; i < mbrs.length; i++) {
				System.out.println("Mbr[" + (i + 1) + "=" + mbrs[i].getName());
			}
			Iterator i = super.entrySet().iterator();
			int cnt = 0;

			while (i.hasNext()) {
				Map.Entry e = (Map.Entry) i.next();
				System.out.println((++cnt) + ". " + super.get(e.getKey()));
			}
			System.out.println("EndMap]\n\n");
		} catch (Exception ignore) {
			ignore.printStackTrace();
		}
	}

	/**
	 * Returns true if the key has an entry in the map. The entry can be a proxy
	 * or a backup entry, invoking <code>get(key)</code> will make this entry
	 * primary for the group
	 * 
	 * @param key
	 *            Object
	 * @return boolean
	 */
	public boolean containsKey(Object key) {
		return super.containsKey(key);
	}

	public Object put(Object key, Object value) {
		return put(key, value, true);
	}

	public Object put(Object key, Object value, boolean notify) {
		MapEntry entry = new MapEntry(key, value);
		entry.setBackup(false);
		entry.setProxy(false);
		entry.setPrimary(channel.getLocalMember(false));

		Object old = null;

		// make sure that any old values get removed
		if (containsKey(key))
			old = remove(key);
		try {
			if (notify) {
				Member[] backup = publishEntryInfo(key, value);
				entry.setBackupNodes(backup);
			}
		} catch (ChannelException x) {
			log
					.error(
							"Unable to replicate out data for a LazyReplicatedMap.put operation",
							x);
		}
		super.put(key, entry);
		return old;
	}

	/**
	 * Copies all values from one map to this instance
	 * 
	 * @param m
	 *            Map
	 */
	public void putAll(Map m) {
		Iterator i = m.entrySet().iterator();
		while (i.hasNext()) {
			Map.Entry entry = (Map.Entry) i.next();
			put(entry.getKey(), entry.getValue());
		}
	}

	public void clear() {
		clear(true);
	}

	public void clear(boolean notify) {
		if (notify) {
			// only delete active keys
			Iterator keys = keySet().iterator();
			while (keys.hasNext())
				remove(keys.next());
		} else {
			super.clear();
		}
	}

	public boolean containsValue(Object value) {
		if (value == null) {
			return super.containsValue(value);
		} else {
			Iterator i = super.entrySet().iterator();
			while (i.hasNext()) {
				Map.Entry e = (Map.Entry) i.next();
				MapEntry entry = (MapEntry) super.get(e.getKey());
				if (entry != null && entry.isPrimary()
						&& value.equals(entry.getValue()))
					return true;
			}// while
			return false;
		}// end if
	}

	public Object clone() {
		throw new UnsupportedOperationException(
				"This operation is not valid on a replicated map");
	}

	/**
	 * Returns the entire contents of the map Map.Entry.getValue() will return a
	 * LazyReplicatedMap.MapEntry object containing all the information about
	 * the object.
	 * 
	 * @return Set
	 */
	public Set entrySetFull() {
		return super.entrySet();
	}

	public Set keySetFull() {
		return super.keySet();
	}

	public int sizeFull() {
		return super.size();
	}

	public Set entrySet() {
		LinkedHashSet set = new LinkedHashSet(super.size());
		Iterator i = super.entrySet().iterator();
		while (i.hasNext()) {
			Map.Entry e = (Map.Entry) i.next();
			Object key = e.getKey();
			MapEntry entry = (MapEntry) super.get(key);
			if (entry != null && entry.isPrimary()) {
				set.add(new MapEntry(key, entry.getValue()));
			}
		}
		return Collections.unmodifiableSet(set);
	}

	public Set keySet() {
		// todo implement
		// should only return keys where this is active.
		LinkedHashSet set = new LinkedHashSet(super.size());
		Iterator i = super.entrySet().iterator();
		while (i.hasNext()) {
			Map.Entry e = (Map.Entry) i.next();
			Object key = e.getKey();
			MapEntry entry = (MapEntry) super.get(key);
			if (entry != null && entry.isPrimary())
				set.add(key);
		}
		return Collections.unmodifiableSet(set);

	}

	public int size() {
		// todo, implement a counter variable instead
		// only count active members in this node
		int counter = 0;
		Iterator it = super.entrySet().iterator();
		while (it != null && it.hasNext()) {
			Map.Entry e = (Map.Entry) it.next();
			if (e != null) {
				MapEntry entry = (MapEntry) super.get(e.getKey());
				if (entry != null && entry.isPrimary()
						&& entry.getValue() != null)
					counter++;
			}
		}
		return counter;
	}

	protected boolean removeEldestEntry(Map.Entry eldest) {
		return false;
	}

	public boolean isEmpty() {
		return size() == 0;
	}

	public Collection values() {
		ArrayList values = new ArrayList();
		Iterator i = super.entrySet().iterator();
		while (i.hasNext()) {
			Map.Entry e = (Map.Entry) i.next();
			MapEntry entry = (MapEntry) super.get(e.getKey());
			if (entry != null && entry.isPrimary() && entry.getValue() != null)
				values.add(entry.getValue());
		}
		return Collections.unmodifiableCollection(values);
	}

	// ------------------------------------------------------------------------------
	// Map Entry class
	// ------------------------------------------------------------------------------
	public static class MapEntry implements Map.Entry {
		private boolean backup;
		private boolean proxy;
		private Member[] backupNodes;
		private Member primary;
		private Object key;
		private Object value;

		public MapEntry(Object key, Object value) {
			setKey(key);
			setValue(value);

		}

		public boolean isKeySerializable() {
			return (key == null) || (key instanceof Serializable);
		}

		public boolean isValueSerializable() {
			return (value == null) || (value instanceof Serializable);
		}

		public boolean isSerializable() {
			return isKeySerializable() && isValueSerializable();
		}

		public boolean isBackup() {
			return backup;
		}

		public void setBackup(boolean backup) {
			this.backup = backup;
		}

		public boolean isProxy() {
			return proxy;
		}

		public boolean isPrimary() {
			return ((!proxy) && (!backup));
		}

		public void setProxy(boolean proxy) {
			this.proxy = proxy;
		}

		public boolean isDiffable() {
			return (value instanceof ReplicatedMapEntry)
					&& ((ReplicatedMapEntry) value).isDiffable();
		}

		public void setBackupNodes(Member[] nodes) {
			this.backupNodes = nodes;
		}

		public Member[] getBackupNodes() {
			return backupNodes;
		}

		public void setPrimary(Member m) {
			primary = m;
		}

		public Member getPrimary() {
			return primary;
		}

		public Object getValue() {
			return value;
		}

		public Object setValue(Object value) {
			Object old = this.value;
			this.value = value;
			return old;
		}

		public Object getKey() {
			return key;
		}

		public Object setKey(Object key) {
			Object old = this.key;
			this.key = key;
			return old;
		}

		public int hashCode() {
			return key.hashCode();
		}

		public boolean equals(Object o) {
			return key.equals(o);
		}

		/**
		 * apply a diff, or an entire object
		 * 
		 * @param data
		 *            byte[]
		 * @param offset
		 *            int
		 * @param length
		 *            int
		 * @param diff
		 *            boolean
		 * @throws IOException
		 * @throws ClassNotFoundException
		 */
		public void apply(byte[] data, int offset, int length, boolean diff)
				throws IOException, ClassNotFoundException {
			if (isDiffable() && diff) {
				ReplicatedMapEntry rentry = (ReplicatedMapEntry) value;
				try {
					rentry.lock();
					rentry.applyDiff(data, offset, length);
				} finally {
					rentry.unlock();
				}
			} else if (length == 0) {
				value = null;
				proxy = true;
			} else {
				value = XByteBuffer.deserialize(data, offset, length);
			}
		}

		public String toString() {
			StringBuffer buf = new StringBuffer("MapEntry[key:");
			buf.append(getKey()).append("; ");
			buf.append("value:").append(getValue()).append("; ");
			buf.append("primary:").append(isPrimary()).append("; ");
			buf.append("backup:").append(isBackup()).append("; ");
			buf.append("proxy:").append(isProxy()).append(";]");
			return buf.toString();
		}

	}

	// ------------------------------------------------------------------------------
	// map message to send to and from other maps
	// ------------------------------------------------------------------------------

	public static class MapMessage implements Serializable {
		public static final int MSG_BACKUP = 1;
		public static final int MSG_RETRIEVE_BACKUP = 2;
		public static final int MSG_PROXY = 3;
		public static final int MSG_REMOVE = 4;
		public static final int MSG_STATE = 5;
		public static final int MSG_START = 6;
		public static final int MSG_STOP = 7;
		public static final int MSG_INIT = 8;
		public static final int MSG_COPY = 9;
		public static final int MSG_STATE_COPY = 10;

		private byte[] mapId;
		private int msgtype;
		private boolean diff;
		private transient Serializable key;
		private transient Serializable value;
		private byte[] valuedata;
		private byte[] keydata;
		private byte[] diffvalue;
		private Member[] nodes;
		private Member primary;

		public String toString() {
			StringBuffer buf = new StringBuffer("MapMessage[context=");
			buf.append(new String(mapId));
			buf.append("; type=");
			buf.append(getTypeDesc());
			buf.append("; key=");
			buf.append(key);
			buf.append("; value=");
			buf.append(value);
			return buf.toString();
		}

		public String getTypeDesc() {
			switch (msgtype) {
			case MSG_BACKUP:
				return "MSG_BACKUP";
			case MSG_RETRIEVE_BACKUP:
				return "MSG_RETRIEVE_BACKUP";
			case MSG_PROXY:
				return "MSG_PROXY";
			case MSG_REMOVE:
				return "MSG_REMOVE";
			case MSG_STATE:
				return "MSG_STATE";
			case MSG_START:
				return "MSG_START";
			case MSG_STOP:
				return "MSG_STOP";
			case MSG_INIT:
				return "MSG_INIT";
			case MSG_STATE_COPY:
				return "MSG_STATE_COPY";
			case MSG_COPY:
				return "MSG_COPY";
			default:
				return "UNKNOWN";
			}
		}

		public MapMessage() {
		}

		public MapMessage(byte[] mapId, int msgtype, boolean diff,
				Serializable key, Serializable value, byte[] diffvalue,
				Member primary, Member[] nodes) {
			this.mapId = mapId;
			this.msgtype = msgtype;
			this.diff = diff;
			this.key = key;
			this.value = value;
			this.diffvalue = diffvalue;
			this.nodes = nodes;
			this.primary = primary;
			setValue(value);
			setKey(key);
		}

		public void deserialize(ClassLoader[] cls) throws IOException,
				ClassNotFoundException {
			key(cls);
			value(cls);
		}

		public int getMsgType() {
			return msgtype;
		}

		public boolean isDiff() {
			return diff;
		}

		public Serializable getKey() {
			try {
				return key(null);
			} catch (Exception x) {
				log.error("Deserialization error of the MapMessage.key", x);
				return null;
			}
		}

		public Serializable key(ClassLoader[] cls) throws IOException,
				ClassNotFoundException {
			if (key != null)
				return key;
			if (keydata == null || keydata.length == 0)
				return null;
			key = XByteBuffer.deserialize(keydata, 0, keydata.length, cls);
			keydata = null;
			return key;
		}

		public byte[] getKeyData() {
			return keydata;
		}

		public Serializable getValue() {
			try {
				return value(null);
			} catch (Exception x) {
				log.error("Deserialization error of the MapMessage.value", x);
				return null;
			}
		}

		public Serializable value(ClassLoader[] cls) throws IOException,
				ClassNotFoundException {
			if (value != null)
				return value;
			if (valuedata == null || valuedata.length == 0)
				return null;
			value = XByteBuffer
					.deserialize(valuedata, 0, valuedata.length, cls);
			valuedata = null;
			;
			return value;
		}

		public byte[] getValueData() {
			return valuedata;
		}

		public byte[] getDiffValue() {
			return diffvalue;
		}

		public Member[] getBackupNodes() {
			return nodes;
		}

		private void setBackUpNodes(Member[] nodes) {
			this.nodes = nodes;
		}

		public Member getPrimary() {
			return primary;
		}

		private void setPrimary(Member m) {
			primary = m;
		}

		public byte[] getMapId() {
			return mapId;
		}

		public void setValue(Serializable value) {
			try {
				if (value != null)
					valuedata = XByteBuffer.serialize(value);
				this.value = value;
			} catch (IOException x) {
				throw new RuntimeException(x);
			}
		}

		public void setKey(Serializable key) {
			try {
				if (key != null)
					keydata = XByteBuffer.serialize(key);
				this.key = key;
			} catch (IOException x) {
				throw new RuntimeException(x);
			}
		}

		protected Member[] readMembers(ObjectInput in) throws IOException,
				ClassNotFoundException {
			int nodecount = in.readInt();
			Member[] members = new Member[nodecount];
			for (int i = 0; i < members.length; i++) {
				byte[] d = new byte[in.readInt()];
				in.read(d);
				if (d.length > 0)
					members[i] = MemberImpl.getMember(d);
			}
			return members;
		}

		protected void writeMembers(ObjectOutput out, Member[] members)
				throws IOException {
			if (members == null)
				members = new Member[0];
			out.writeInt(members.length);
			for (int i = 0; i < members.length; i++) {
				if (members[i] != null) {
					byte[] d = members[i] != null ? ((MemberImpl) members[i])
							.getData(false) : new byte[0];
					out.writeInt(d.length);
					out.write(d);
				}
			}
		}

		/**
		 * shallow clone
		 * 
		 * @return Object
		 */
		public Object clone() {
			MapMessage msg = new MapMessage(this.mapId, this.msgtype,
					this.diff, this.key, this.value, this.diffvalue,
					this.primary, this.nodes);
			msg.keydata = this.keydata;
			msg.valuedata = this.valuedata;
			return msg;
		}
	} // MapMessage

	public Channel getChannel() {
		return channel;
	}

	public byte[] getMapContextName() {
		return mapContextName;
	}

	public RpcChannel getRpcChannel() {
		return rpcChannel;
	}

	public long getRpcTimeout() {
		return rpcTimeout;
	}

	public Object getStateMutex() {
		return stateMutex;
	}

	public boolean isStateTransferred() {
		return stateTransferred;
	}

	public MapOwner getMapOwner() {
		return mapOwner;
	}

	public ClassLoader[] getExternalLoaders() {
		return externalLoaders;
	}

	public int getChannelSendOptions() {
		return channelSendOptions;
	}

	public long getAccessTimeout() {
		return accessTimeout;
	}

	public void setMapOwner(MapOwner mapOwner) {
		this.mapOwner = mapOwner;
	}

	public void setExternalLoaders(ClassLoader[] externalLoaders) {
		this.externalLoaders = externalLoaders;
	}

	public void setChannelSendOptions(int channelSendOptions) {
		this.channelSendOptions = channelSendOptions;
	}

	public void setAccessTimeout(long accessTimeout) {
		this.accessTimeout = accessTimeout;
	}

}